640217356 has 6 divisors (see below), whose sum is σ = 1120380380. Its totient is φ = 320108676.

The previous prime is 640217341. The next prime is 640217371. The reversal of 640217356 is 653712046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640217341) and next prime (640217371).

It is a super-3 number, since 3×640217356³ (a number of 27 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80027166 + ... + 80027173.

Almost surely, 2^640217356 is an apocalyptic number.

It is an amenable number.

640217356 is a deficient number, since it is larger than the sum of its proper divisors (480163024).

640217356 is a wasteful number, since it uses less digits than its factorization.

640217356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160054343 (or 160054341 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 640217356 is about 25302.5167918134. The cubic root of 640217356 is about 861.8714231595.

The spelling of 640217356 in words is "six hundred forty million, two hundred seventeen thousand, three hundred fifty-six".